making cairo mandatory in vcl

[Caolán McNamara]

On Sat, 2015-11-14 at 17:00 +0100, Riccardo Magliocchetti wrote:
> Hi Caolàn, all,
> 
> in [0] and [1] you made cairo mandatory for *nix platforms. This
> breaks 
> --without-x but that's no big deal, i'll add some specific ifdefery.
> I have a couple of questions:
> - is there a plan to kill non cairo rendering?

I'd like to yes. The non-cairo text rendering is only used in the svp
path at the moment. i.e. basically I'd move the gtk3 use of cairo text
rendering down to svp and have it for all svp using platforms, allowing
a big piece of code to be deleted and have one text-rendering path
instead of two there.

> - does it make sense to keep enable-cairo-canvas switch?

Well, at the moment having cairo enabled and having the cairo *canvas*
enabled are conflated together. Part of the patch de-confuses that and
separates use of cairo for drawing stuff to the svp backend versus
having the cairo canvas thing enabled. So I've no opinion on enable
-cairo-canvas, but the non-canvas code that are basically incorrectly
lumped under that ifdef would be removed out of it.

Because the svp vcl stuff is used by android as well as the gtk3
backend, I've reverted this work for now until I experiment if I can
get cairo built for android and confirm that using it for text
rendering on that platform works fine before progressing.

C.